lecture 21 fertilizer2

SilvicultureFORS 3347

Instructor: Dr. Jeremy StovallLecture 21:

Intermediate Treatments – Forest Nutrition II

Context

FORS 3347 Lecture 21 Revised 01.18.2016 2

Stand Establishment

Intermediate Treatments

Regeneration Treatments

Context


Outline

A. How do nutrients cycle?B. Is your stand nutrient limited?C. When should you fertilize?D. How much should you fertilize?E. How is fertilizer applied?F. How do stands respond?

4FORS 3347 Lecture 21 Revised 01.18.2016

How much fertilizer should you apply?

5

Source: Fox, T. R., Allen, H. L., Albaugh, T. J., Rubilar, R., & Carlson, C. A. (2007). Tree nutrition and forest fertilization of pine plantations in the southern United States. Southern Journal of Applied Forestry, 31(1), 5‐11.

FORS 3347 Lecture 21 Revised 01.18.2016

Determining Fertilizer Rates

N P KExpressed elemental N P2O5 K2O

Elemental Weight 14.00 30.97 39.10

Atoms of Target Element 1 2 2

Weight of Target Element Only 14.00 61.94 78.20

Weight of Entire Molecule* 14.00 141.94 94.20

Conversion to Elemental 100% 44% 83%

* Atomic weight of oxygen = 16.00


Determining Fertilizer RatesMaterial Analysis Comments

Nitrogen Materials

urea 45‐0‐0 Volatilization an issue

ammonium nitrate 33‐0‐0 Hydroscopic & explosive (no longer sold)

diammonium phosphate (DAP) 18‐46‐0 Primary P source

Phosphorous materials

Concentrated superphosphate 0‐44‐0 Common water‐soluble P‐fertilizer

DAP 18‐46‐0 Water soluble N & P

Rock phosphate 0‐15‐0 Not water soluble, but soluble in acids

Potassium Materials

Muriate of potash 0‐0‐60 Common K fertilizer; water soluble


Determining Fertilizer RatesPrescribe (i.e. What do you need per acre) Apply

ElementFertRate

FertSource

Elemental Ratio

Element Source ScaleFactor

Source (lbs)N P K

N 200Urea45‐0‐0N

45‐0‐0N 177.5 0 0 0.45 395

PStart here b/c DAP contains

N and P

25DAP

18‐46‐0N‐P2O5

18‐20‐0N‐P 22.5 25 0 0.20 125

K 50Potash0‐0‐60

K2O

0‐0‐50K 0 0 50 0.50 100

P2O5 = 43.6% P K2O = 83.3% K


Group Exercise

• How much urea do you need to apply to get 150 lbs per acre of elemental N?• Urea: 45 – 0 – 0

• How much DAP do you need to apply to get 50 lbs per acre of elemental P?• DAP: 18 – 46 – 0; P2O5 = 43.6% P

• How many lbs of N are applied per acre in this DAP prescription?


Objective D Review

• Typical rates are 25 – 50 lbs of P per acre and 150 – 200 lbs of N per acre• Fertilizer rates on a bag of fertilizer are not elemental rates for P or K


Outline



Ground Fertilizer Equipment



13

David Dickens, UGA, Bugwood.org



14

David Dickens, UGA, Bugwood.org



15

John Hodges, MSU, Bugwood.org


Aerial Fertilizer Equipment

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Dave Powell, USDA FS, Bugwood.org


Aerial Fertilizer Equipment

17

Dave Powell, USDA FS, Bugwood.org


Application Considerations

• Application over canopy?• Abundant shrubs?• Tract location?• Near chicken houses or horse farms?


Environmental Considerations

• Drift less of an issue than herbicides• Little mortality, although longleaf can be damaged or killed by loblolly rates

• Still should avoid• Almost any SMZ will keep nutrients out of streams• Can leach on sandy soils

19

http://tfswater.blogspot.com/2002_06_01_archive.html


Checking Contractors

• Collect calibration data• Collect catch data• Place a number of containers of known area in stand

• Weigh fertilizer collected during or following operation

• Scale to per acre basis

20

http://www.caes.uga.edu/Publications/pubDetail.cfm?pk_ID=6393


Objective E Review

• The majority of fertilizer applications in the US South are completed with fixed‐wing aircraft• Some applications are also made by skidders• Many of the same operational considerations we considered with herbicides apply to fertilizers too (e.g. drift, adjacent landowners, stream water quality)


Outline



Response Types

• Different treatments result in different growth responses

• It is important to understand what type of growth response to expect when timing an intermediate operation


0 5 10 15 20 25 30 35

Annu

al height g

rowth

Age (years)

Response Type A

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)


A

Base

A

Base

Response Type A Example

• Treatment results in increased growth EVERY year• P fert on nutrient deficient site


0 5 10 15 20 25 30 35

Annu

al height g

rowth

Age (years)

Response Type B

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)


B

Base

BBase

Response Type B Example

• Initial response that tapers, then paralleling base‐line due to initial gain• Midrotation N fertilizer application (8 years)


0 5 10 15 20 25 30 35

Annu

al height g

rowth

Age (years)

Response Type C

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)


C

BaseC

Base

Response Type C Example

• Initial response, reaches max, then declines back to baseline• Bedding causes better aeration for seedlings, but then response dissipates as water table is drawn down


0 5 10 15 20 25 30 35

Annu

al height g

rowth

Age (years)

Response Type D

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)


BaseDBase

D

Response Type D Example

• Initial gain due to treatment, but control will eventually outcompete treated area• Windrowing on nutrient deficient site


0 5 10 15 20 25 30 35

Annu

al height g

rowth

Age (years)

Response Type E

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)


Base

E

Base

E

Response Type E Example

• Negative response to treatment• “Career limiting move”

• Loss of topsoil


Response Types Compared: Height

0 5 10 15 20 25 30 35

Cumulative he

ight

Age (years)

AB

C

Base


Response Types Compared: Basal Area

0 5 10 15 20 25 30 35

Cumulative Ba

sal A

rea

Age (years)

A

B

BaseC


Response Types Compared: Volume

0 5 10 15 20 25 30 35

Cumulative Vo

lume

Age (years)

A

B

Base

C


Response Types Compared

• A‐type increases carrying capacity of site• B & C‐type accelerate stand development• C type response must be timed appropriately prior to a harvest• Harvest during period of increased gain

• No reason to do type C treatment on longer rotation


Integrated Silvicultural Systems


Fert vs. Fert + Weed Control


Fertilizer + Competition Control


0

100

200

300

400

500

600

700

200N + 50P Herbicide Both

Volume grow

th re

spon

se (ft

3 /acre)

Early FertilizationWeed ControlWoody ControlSite Preparation ResponseBACA

BAC_

BA_A

BA_ _

B_CA

B_C_

B_ _A

B_ _ _

BACA

BAC_

BA_A

BA_ _

B_CA

B_C_

B_ _A

B_ _ _

_ACA

_AC_

_A_A

_A_ _

_ _CA

_ _C_

_ _ _A

_ _ _ _

Combination Plowing

Bedding

None

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

Harvest

Silvicultural Treatments Regimes


Synthesis

• On average, fertilizer application increases growth in southern pine stands• It does not increase the growth of all stands the same• Different stands are limited by different nutrients• There are tools available to determine if a stand is nutrient limited, and by what nutrients

• Fertilizer application can yield economic returns, but not without risks


lecture 21 fertilizer2

Documents

Transcript of lecture 21 fertilizer2